Erik Karlsson, the reigning Norris Trophy winner as the NHL's best defenseman, was putting on another spectacular year. And now it's done. Karlsson suffered a lacerated Achilles tendon as the skate blade of Pittsbugh's Matt Cooke came down on the back of his left foot. He will require surgery and is out indefinitely—almost certainly longer than the two-and-a-half months left in the regular season.

Karlsson and Pittsburgh's Matt Cooke were going for a puck along the boards, on which Karlsson had a step. Cooke—and we need to choose our language carefully here—rode him into the boards, or hit him a split second after he reached the boards, keeping Karlsson's stick high so neither could corral the puck. As they hit, Cooke's skate blade sliced through Karlsson's sock, skin, and apparently Achilles. Karlsson immediately screamed out in pain.

"We all know who's involved in it," Senators coach Paul MacLean said. "That's just the way it is. The injury to Erik was unfortunate, and it happens on a nothing play that could've potentially been whistled down."

"I don't know it it's intent to injure, but I don't know why you would hit somebody like that in that situation."

Karlsson himself was unavailable for comment after the game, but was clearly furious in the immediate aftermath. As he was being helped off the ice, he shouted something at the Pittsburgh bench, presumably for Cooke. But that's anger talking, and disappointment, and the realization that your season's over in February. Cooke's hit wasn't dirty—maybe not strictly necessary, but surely not worthy of a fine or suspension. It's the kind of extra physicality a guy like Cooke is supposed to bring into play—a not-strictly-necessary hit on a team's No. 1 blueliner in the second period translates to a little more hesitation or exhaustion from Karlsson in the third. Cooke's a pest, not a sociopath—hockey players simply don't use their skates as weapons. It's bad luck for the Senators, and bad luck for Karlsson, and Cooke's only punishment may come when the Penguins return to Ottawa in April.